Metal air propeller and the like



oct. 13, 1925. 1,557,311

H. LEITNER METAL AIR PROPELLER AND THE LKE Original Filed Jan. 2l, 1922 Patented Oct. 13, '1925.

PATENT OFFICE.

HENRY LEITNER, F LONDON, ENG-LAND.

METAL AIR PROPELLER AND THE LIKE.

Original application filed January 21, 1922, Serial No. 530,845. Divided and this application filed May 3, 1924. Serial Nb. 710,839.

To aZZ whom t may concern.'

Be it known that l, HENRY LnrrNnR, a subject of the King of Great Britain, residing at Regent l-Iouse, Kingsway, London,

England, have invented new and useful Improvements in Metal Air Propellers and the like, of which the following is a specification.

My invention has reference/'to screw-propellers, mainly for usel on aircraft, of the kind described in my prior Patent No. 1,500,-

606 of July 15, 1924, of which this is a division, and in which the blades are hollow and made of sheet metal, and which are advantageousl detachable from the propeller hub and adjustable therein for variatlons of pitch and consequently vary from an aerofoil cross section in the body to a circular cross section at the root.

According to the invention the blade is made from sheet metal folded to form the edges of the blade and joined at' the meeting edges by a longitudinal mechanical seam extending along one side of the blade intermediate of the two folded edges. Or, the

blade may bemade in two sections, one or the main section of which is folded to ,form both edges of the blade, whilst the other section is joined to the vaforesaid section by longitudinal mechanical seams extending along one side of the blade intermediate of the two folded edges. A To enable the invention to be fully understood I will describe it by reference to the accompanying drawing, in which which Fi ure 1 is an elevation of a hollow sheet meta propeller blade of the type having a cylindrical stem or root designed to turn in a bearing in the propeller hub for varying the pitch, the said blade Vbeing constructed in accordance with the invention..

Figure 2 is a cross section on the lineQ-Q, Figure 1, but drawn to a larger scale, and

Figure 3 is a partial cross section on the line 3 3, Figure 1, also drawn to a larger scale.

Figure 4 is a view similar to Figure 2, illustrating a modification and Figure 5 is a view corresponding to a section takenv on the line 3-3, Figure 1, of the modification shown in Figure t.

Figures 6 and 7 are sections illustrating modifications of the joint in the blade illustra'ted in Figures 2 and 3.

Figurev 8 is a similar view to 'Figure 6 of a modified joint and Figure 9 is a similar view to Figure 8 but taken near the root of the blade.

Figure 10 is amodiication of the joint shown injFigure 9.

Referring to Figures 1 and 2, a is the sheet of metal folded to form the edges of the propeller blade and c, d are the respective bends therein constituting the leading and trailing edges of the blades, the meeting edges of the sheet overlapping at about the centre of the blade and being securedby rivets e; or, they may be secured byy other means. Figure 2 is a section through the top of the blade where only onelamina is employed, whilst Figure 3 is a partial seetion nearer the root of the blade where, say, two additional laminas are used,the overlapping joint beingy arranged as indicated, whereas, where all the laminae enter the cylindrical casing f forming the stem, the rivets e may also pass through the said` caslng.

Figures l andl 5 show thetwo-part construction of blade in which both the joints,

which are shown of the overlap type, are con fined to one face of the blade, as indicating one part of the blade and b the other part. Instead of the overlapping joints described l with reference to Figures 1 to 3, the meeting edges of the part a (or offthe parts a and b) may butt together, as indicated in Figures 6 and 'Z,-the joints being covered by metal strips g secured to the said parts a and b vby rivets h. r, other means than rivets may be employed.

Figures 8, 9 and 10 show dierent forms of folded or tinsmiths joints for uniting the edges of the parts o; and that illustrated in Figure 8 showing the edges of the said parts folded together, the inner laminae in Figure 9 being riveted to the said jointed outer lamina b rivets z'. Figure 10 shows a metal strip j intermediate of the adjacent edges of the parts a and and having the edges connected thereto by folded or tin.- smiths joints.v

Claims: y

1. A. screw-propeller blade of the hind de- 5 blade intermediate of the two folded edges.

2. A screw-propeller blade of the kind described, formed from two sections or" sheet metal, one section of which is folded to form both edges of the blade, Whilst the other sec- 10 tion is joined to the aforesaid section by longitudinal mechanical seams extending one side of the blade intermediate of the two folded edges.

3. A screw-propeller blade of the kind described, formed from two sections of sheet metal, the main section of which is folded to form both edges of the blade, Whilst the intermediate section isjointed to the main section by longitudinal mechanical seams extending along one side of the blade inter- 20 mediate of the two folded edges.

HENRY LEITNER. 

